At Sparta Academy, the deranged and perverted faculty continue to terrorize students with brutal and humiliating punishments for the smallest infractions. Following the events of the first film, the academy remains under the corrupt control of the demonic jester-like principal known as the Toenail of Satan. Good-natured but unfortunate student Mayumi Takahashi once again finds herself as the primary target of these sadistic educators, who devise increasingly elaborate traps not just to torment her, but to finally expose and destroy her mysterious protector.

The faculty’s latest scheme involves accusing Mayumi and her classmates of cheating, a pretext to send them to the school’s notorious torture room where a sinister device awaits. This punishment is a deliberate ruse, designed specifically to force the appearance of the legendary masked heroine, Kekko Kamen. As the teachers prepare to enact their cruel disciplinary measures, their plan succeeds in summoning their intended target.

True to form, Kekko Kamen arrives to deliver justice. The superheroine is a striking and bizarre vision of fearless resolve, wearing only a red rabbit-eared mask, long red gloves, a red scarf, and red boots. Wielding nunchaku with acrobatic grace, she confronts the school’s faculty members, using her unorthodox fighting style and signature finishing move—a leaping, crotch-first drop onto her opponent’s face—to dispatch the corrupt teachers one by one.

The narrative arc follows the continuing cat-and-mouse game between the masked vigilante and the Toenail of Satan. While the principal is obsessed with uncovering Kekko Kamen’s secret identity, often focusing his suspicions on students like Mayumi or the athletic P.E. teacher Keiko Natsuwata, the heroine’s true origin remains a mystery. The conflict deepens as the academy brings in new enforcers or devises fresh tortures, only for Kekko Kamen to reappear, seemingly unstoppable. As the title We'll be back... suggests, the film reaffirms the cyclical nature of this struggle, ending with the promise that both the forces of perverted authority and their near-naked nemesis will return to fight another day.